George McIntyre
48 lines
1.8 KiB
C++
48 lines
1.8 KiB
C++
/*
|
|
* Copyright - See the COPYRIGHT that is included with this distribution.
|
|
* pvxs is distributed subject to a Software License Agreement found
|
|
* in file LICENSE that is included with this distribution.
|
|
*
|
|
* Author George S. McIntyre <george@level-n.com>, 2023
|
|
*
|
|
*/
|
|
|
|
#include "fieldsubscriptionctx.h"
|
|
|
|
namespace pvxs {
|
|
namespace ioc {
|
|
|
|
/**
|
|
* Called when a client wishes to subscribe to a group. The onSubscribe method calls this method for each
|
|
* field within the group. This method will create a new event subscription and attach it to this field
|
|
* subscription context.
|
|
*
|
|
* @param pEventCtx the global event context which references the db event propagation framework
|
|
* @param subscriptionCallback reference to a callback function to be called when the field is updated.
|
|
* @param selectOptions the selection options to determine events to be monitored. DBE_VALUE | DBE_ALARM | DBE_PROPERTY
|
|
* @param forValues true if this should monitor value changes, false for property changes.
|
|
*/
|
|
void FieldSubscriptionCtx::subscribeField(dbEventCtx pEventCtx, EVENTFUNC (* subscriptionCallback),
|
|
unsigned int selectOptions, bool forValues) {
|
|
auto& pDbChannel = (forValues ? field->value.channel : field->properties.channel).shared_ptr();
|
|
auto& pEventSubscription = forValues ? pValueEventSubscription : pPropertiesEventSubscription;
|
|
pEventSubscription.reset(
|
|
db_add_event(
|
|
pEventCtx,
|
|
pDbChannel.get(),
|
|
subscriptionCallback,
|
|
this, selectOptions),
|
|
[](dbEventSubscription pEventSub) {
|
|
if (pEventSub) {
|
|
db_cancel_event(pEventSub);
|
|
}
|
|
});
|
|
|
|
if (!pEventSubscription) {
|
|
throw std::runtime_error("Failed to create db subscription");
|
|
}
|
|
}
|
|
|
|
} // pvcs
|
|
} // ioc
|